Electrical transmission device



J1me 1931- J. D. HILLIARD ELECTRICAL TRANSMISSION DEVICE Filed June 10 1929 Inventor John D. HLLL'Ldrcl by H'Ls Attorney.

P........1 June 9-, 1931 UNITED STATES ATE T OFFICE j JOHN D. HILLLABD, OF SCHENEC'I'ADY, NEW YORK, ASSIGNOB 'IO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK ELECTRICAL TRANSMISSION DEVICE Application fled June 10,

My invention relates to circuit breakers and more particularly to circuit breakers o the fluid break type having a comparatively large interrupting capacity. In "oilfi'circuit breakers of the type adapted for interrupting currents at high potentials, there are developed by the power are durin interruption of the circuit, large quantitles of gases which project aportion of the 10 oil body upwardly with great force against the cover structure to cause hi h, sudden, in-

ternal pressures within thecircuit breaker housing. It is generally true that the interruptin capacity of an oil switch depends upon t e strength of the switch housing'to withstand these large and violent internal pressures withoubmechanical failure. In addition to these} pressures, due to the sudden generation of ases by the action of the power are on the 011 or other are extinguishig medium, a secondary explosion may be caused by a spark coming into contact with the inflammable gases in the upper part of the switch housing, as, for example, by a s ark from the leads of the current trans- I fsrmer which is generally disposed adjacent one of the contact'or studs and carried by the switch cover structure. Notwithstanding the ability of the switch housing to with- 80 stand these internal explosions, one or more of the conductor insulators supported by the housing, which generally comprise a bushing member of ceramic material as orcelain or the like, may be subjected to vio ent stresses by vibrations set u in the cover structure upon occurrence 0 these sudden pressures or explosions. "Dueto the fact that the insulatm bushing is generally of brittle material, and radius of ration, these vibrations may be of such or er of magnitude as to cause fracture and consequent failure of the bushin object of my invention is toprovide mounting structure for the insulatingbushing,'ofsuch character that transmission of shock between the switch housing proper and the insulatin bushing is substantially reduced or eliminated. I Another object of my invention is to proaving considerable mass.

1929. Serial N0. 889,904.

vide means for preventing the above described secondary explosion within the breaker housing by isolating the current transformer structure from the gas-containing space in the upper portion of the breaker housmg.

For a better understanding of my invention, reference may be had to the following description taken in connection .with the accompanying drawin in which the single figure is a view part y in section of one embodiment of my invention.

An oil circuit breaker of a well known type is partially illustrated and comprises by way of example an outer shell, or tank 1, containmg an arc extinguishing medium 2, as an oilbath within ,wh1ch. is1mmersed a movable contact or bridging member 3 co-acting with a so-called ex losipn'chamber, 4, 1n the usual manner. he \u per portion of tank 1 has mounted thereon in any suitable manner a metallic cover structure 5 of steel for example adapted to su port and position a leadin conductor stud inotshown), and its associated insulating ushing 6, which is generally composedv of porcelain or other hard and comparatively brittle material. The insulating bushing '6 is secured at 7, as by cement, to an annular flange 8, likewise suitably secured, as by bolts 9, to a supporting plate-like member 10, having an annular depending flange 11 for a purpose hereinafter described.

Mounted u on the to of cover structure 5 is an annular y flange member 12 with re-' spect to which member 10 is resiliently mounted for limited universal movement. To this end, cushioning material 13, comprising any suitable resilient aperiodic material, as'for example rubber, cork board or equivalent, is lnterposed generally in the form of a asket, between members 10 and 12, so that t are is no metal-to-metal contact between them. Due to the fact that the cover structure of the breaker is generally of steel, sudden large internal pressures acting thereon tend to causedeformation orbulgmg of the same, with the result that the insulating bushing is forced out of its normal alignment.

. In the mountingstructur'e above referred to, the bushing is permitted a limited universal movement, i. e. axial and tilting movement with respect to the cover structure, thereby greatly reducing stresses due to the above described pressures. Accordingly, vibrations or stresses set up in the cover struc ture 5 are not readily transmitted to the supporting member 10 to cause fracture of the ushlng. Member 10 is clamped into position with respect to the cover structure by means of bolts 14 extending through the outer flanged portion of member 10, and secured to member 12. The bolts 14 co-act with metallic washers, or the like, spaced from member 10 by bushings 16, likewise of suitable resilient aperiodic material, thereb preventing transmission of shock to mem er 10 through its clampin structure while permitting limited universa movement of the bushing.

Disposed within the depending annular flange 11, previously referred to, is a bushing current transformer 17 which is disposed in the usual manner around a conductor stud. The lower portion of the transformer housing is enclosed by a plate 18 secured to the lower edge of flange 11, as by bolts 19, and to the lower edge of a metallic ring 20, secured and sealed as by cement 7 to bushing 6. In order to effect an hermetically tight joint, and to properly cushion the respective parts suitably, aperiodic material 21 1s interposed between plate 18 and the coil structure. The usual grounding shield 22 is secured, as by screw threaded engagement, to ring :20 to function in a manner well known in the art.

The leads, (not shown), from the bushing transformer 17 are adapted to extend exteriorly of the cover structure through conduit 23. Accordingly, it will be noted that the transformer structure is hermetically sealed with respect to the interior of the circuit breaker housing so that sparks from the leads to the current transformer, due to abnormal current conditions, are reclud'ed from igniting the high inflamma le gases which collect in the upper portion, or gas-containing space, of the breaker housing upon interruption of the main circuit. Secondary ex plosions due to the ignition of these gases are therefore materiall reduced with resultant decrease of depreciation of the apparatus.

In the event of unsually violent internal explosions within the circuit breaker housing, the shock, which would otherwise be transmitted directly to the more or less brit tle insulating bushing '6, is materially absorbed by the a riodic cushionin structure 13 and 16 so t at the insulating ushing 4, which is of comparatively eat mass and size, is protected-from mechanical failure due to the above mentioned causes.

It shall be understoodthat the terms brittle as used in the above specification and appended claims, is intended to include properties of the commonly used solid insulating materials which are capable of small deformation, as compared with steel, without fracture.

It shall be further understood that various changes in the structure illustrated may be made without departing from the spirit of my invention; for example, members 8 and 10 may comprise a single integral mounting plate, if desired, in which event the trans former housing structure is disposed above instead of beneath the upper portion of the cirouit breaker housing, thereby obviating the necessity of further sealing.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. The combination with a metallic circuit breaker housing and insulating structure of brittle material supported thereby, of cushioning means interposed between said housing and structure for substantially precluding transmission of shock from said housing to said structure.

2. The combination with a steel circuit breaker housing and an insulating bushing of brittle material supported thereby, of aperiodic means interposed between said hous ing and bushin for substantially precluding transmission 0% vibration due to concussion from said housing to said bushing.

3. In a circuit breaker of the type evolvin quantities of gases during interruption o the circuit, the combination with housing structure and insulating structure supported thereby, of resilient shock absorbing means interposed between said structures for preventing failure of said insulating structure.

4. The combination with an oil circuit breaker comprising an oil containing receptacle within which contact structure is disposed, steel cover structure for said receptacle and a conductor insulating bushing of brittle material mounted on said cover structure, of shock absorbing means interposed between said cover structure and insulating bushing for substantially precluding transmission of vibration from said cover structure to said bushing. I

5. The combination with an oil circuit breaker comprising a main housing, cover structure for said housing and an insulatin bushing of brittle material mounted on sai cover structure, 'of means resiliently mounting said bushing to permit limited universal movement of the same with respect to said cover structure comprising a supporting member secured to said bushing, aperiodic means interposed between said supporting member and cover structure, and means resiliently clamping said supporting member to said cover structure.

6. The combination with a circuit breaker of the type evolving combustible gases during interruption of the circuit, comprising a housing having a gas-containing space in the III upper part thereof, and transformer structure mounted on .said housing and within said gas-containing space, of means hermetically sealing said transformer structure with respect to said gas-containin space.

7. In an oil circuit brea er comprising housing structure having a gas-containing space in the upper part thereof and an insulating bushing mounted on and extending through said housing, the combination of a supporting member secured to said bushing, aperiodic means interposed between said member and housing structure so that relative movement between said housing and supporting member is permitted, transformer structure mounted on and depending from said supporting member into said gas-containing space, and enclosing meanshermetically sealing said transformer structure from gases evolved within the circuit breaker housing.

8. In an oil circuit breaker comprisin a metallic housing structure and an insulating bushing of brittle material mounted thereon, the combination of a supporting plate-like member rigidl secured to said bushing, a gasket of yiel ing aperiodic material dis-. posed between said plate-like member and housing structure permitting limited universal movement of said bushing with respect to said housing, and clam ing members yieldingly urging said plate-1i e memberinto firm seating engagement with said gasket.

In witness whereof, I have hereunto set my hand this sixth day of June 1929.

JOHN D. HILLIARD. 

